Admiral 14R12 Restoration

[Crist Rigott]

Originally Posted by Kevin Kuehn

That seems really strange. I think someone mentioned earlier that most service grade sweep generators won't produce a pure sine wave, and also there's no way to get an accurate frequency reading if there's any frequency modulation(sweep) turned on. So it's very possible your counter is picking up on a false harmonic. Another thought is it's possible that your local oscillator is producing something other than the correct IF frequency. But if the IF slugs are back to their original positions that's not very likely, not unless someone else had that thing incorrectly aligned long before you got your hands on it. But at any rate the fact that you're getting the best video and sound with a single peaked frequency response is very strange.

Kevin,

The frequency I'm measuring is the maker frequency, not the sweep frequency. My Freq. Counter is "tapped" off the Marker Osc. tube. It is rock steady when varying the sweep frequency. It should be because they use different oscillators.

Is there a way to measure the local osc freq? It does look like it is half of the 6J6 tube. If so what would I expect from channel 3. That's what my D to A converter and my RF modulator are set to.

[Kevin Kuehn]

There's a lot of variables involved in simply connecting your counter into that circuit. Same reasons you don't hook your scope prob into a high frequency oscillator circuit without expecting it to de-tune the circuit.

Does your 369's marker dial track your counter's reading at various locations on the dial?

[Crist Rigott]

Originally Posted by Kevin Kuehn

There's a lot of variables involved in simply connecting your counter into that circuit. Same reasons you don't hook your scope prob into a high frequency oscillator circuit without expecting it to de-tune the circuit.

Does your 360's marker dial track your counter's reading at various locations on the dial?

OK.

Yes, the marker dial does track the counters readings across the dial on all bands.

[Kevin Kuehn]

When you had the IF aligned to 24.3MC, did you try adjusting the oscillator slug for channel 3 (Sams reference A19) while you had your DVD player playing through the rf modulator? Also A8 is the master oscillator adjustment that will offset all channels equally. If you look at the schematic you will see A8 is a trimmer cap in parallel with the fine tuning control. A9-A20 are the individual slugs for each channels oscillator coil. Those adjustments combined are what sets the correct oscillator frequency that in turn is mixed with the input rf, and is sent into the video IF. Another possibility is that if someone had the tuner coils out they may have gotten them mixed up and not installed back in the correct order, in which case channel 3 may not really be creating the correct oscillator freq for channel 3.

[Crist Rigott]

Originally Posted by Kevin Kuehn

When you had the IF aligned to 24.3MC, did you try adjusting the oscillator slug for channel 3 (A19) while you had your DVD player playing through the rf modulator?

No. Maybe I should try that?

[Kevin Kuehn]

I think so. Also see what I just added to my last post. If the tuner is goofed up there's no way it can send out the correct IF frequency for the channel you think you're receiving.

[Crist Rigott]

Does this turret tuner look right to you? I would think the inserts would go numerically in order.